Synergistic insecticidal compositions



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SYNERGISTIC INSECTICIDAL COMPOSITIONS No Drawing. Original application Mar. 24, 1 -955, Ser..

No. 496,596. Divided and this application Oct. 17, 1958, Ser. No. 767,782

' 2 Claims. (Cl. 167-22).

This invention relates broadly to insecticidal compositions, and more particularly to insecticidal compositions containing phenyl N-carbamate and 0,0-dimethyl S,-(1,2- dicarbethoxyethyl) dithiophosphate, hereinafter referred to as Malathion. More particularly, this invention relates to synergistic insecticidal compositions of these compounds wherein the insecticidal effectiveness of each component is enhanced by the presence of the other to produce an unexpected combined eflect. 1

When two or more substances in combination'show an unexpected high activity, as, for instance, insecticidal activity,- the resulting phenomenon is called synergism. The mechanism of synergism is by no means understood. It is, in fact, quite probable that it differs with difierent synergistic combinations. The term synergism can be defined, however, as a cooperative action which is encountered in combinations of two or more biologically active components in which the combined activity of the two components exceeds the sum of the activities of the components when used alone. The insecticidal activity of the mixed components cannot be predicted from known values of the individual components, but is unpredictable and depends on the individual activity of neither.

It is an object of this invention to provide insecticidal compositions of enhanced killing power. Another object of this invention is to produce novel compositions containing compounds capable of synergizing the knockdown and killing properties of individual toxicants. A further object of this invention is to provide compositions including a relatively toxic phosphorus containing insecticide in which superior insecticidal activity is obtained because of the synergistic effects, but in which the ultimate toxicity to Warm-blooded animals is greatly reduced because of the lower concentrations of the phosphorous compounds required when used in combination with the relatively less toxic carbamates. Other objects and advantages of the invention will become apparent from the description of the invention set forth below.

According to this invention, there are provided synergistic insecticidal compositions comprising 0,0-dimethyl S (1,2 dicarbethoxyethyl) dithiophosphate, hereafter called Malathion, and phenyl N-carbamate. This carbamate may be prepared as described in copending application Serial No. 812,113, filed May 11, 1959.

The synergistic insecticidal compositions of this invention may be used on a wide variety of insect and mite species, but are particularly eiiective against two-spotted spider mites. The combinations are highly effective and economical to use for such large-scale insecticidal requirements as the control of truck crop, forage crop and orchard insects.

The synergistic compositions of this invention can be formulated as aqueous emulsions, as dry or wettable powders, as solutions or in any other suitable vehicle. The

b tates Patent insecticidal compositions can be utilized as sprays, as dusts, as aerosol mixtures, insecticidal coating compositions, and as residues. In general, they can be applied by methods commonly used for control or eradication of insects, mites and the like. Thus these insecticidal compositions .can be formulated with solvents, diluents and carrier media, adhesives, spreading, wetting and emulsifying agents and other ingredients. v i

The relative proportions of the active ingredients as well as inert carriers, solvents, dispersants and the like may vary within wide limits.

Thus the relative proportion (ratio) of the Malathion to the phenyl N-carbamate can range from 20 parts of the former per 1 partof the latter to 1 part of the former per 40 parts of the latter and preferably about 1 part ofthe former to about 2 parts of the latter.

The quantities of the component toxicants in the final insecticidal compositions can range from 0.01% to 25.00% for the Malathionand from 0.05% to 50.00% for the carbamate, and preferably from 0.10% to 10.00% for the Malathion and from 0.10% to 25.00% for the carbamate. V x

The procedures of the testing method are described below. The details of the test experiments including the type of formulation and mode of application or closing, and the species of insects which served as test subjects are given in the examples. r

The test method used is described as follows:

Dust tower method-This general method is described in the following reference, Moore, J. Econ. But. 43, No. 2, 188-190 (1950).

The dusting apparatus consists of a vertical glass cylinder, 34 inches high and 8.5 inches in diameter, into which the appropriate dust sample is discharged through a small hole in the center of the cover, by means of a small laboratory duster operating at an air pressure of "40 p.s.i.g.

The duster assembly comprises a 10 ml. beaker, into V which the weighed sample is placed, and fitted with a rubber stopper. through which pass the air inlet and dust outlet tubes, both ofwhich are made of inch diameter copper tubing. At the outer end of the air inlet tube is bottom of the beaker. The end of is sealed but, along 1 the sides, seven 0.032 inch holes are drilled at irregular intervals which serve as air inlets. Such an arrangement causes pronounced turbulence of the dust and thus insures exhausting the complete sample from the beaker. The dust outlet tube forms an arch from the top of the beaker to the top of the glass dusting tower.

After discharge of the sample into the tower, there is allowed a 2-minute settling time before removal of foliage or insects being treated. A weighed metal plate is placed in the tower each time a test is made, and by weighing the amount of dust deposited on it, it is then possible to calculate the amount applied per acre.

Because of day-to-day variations in the results obtained by this test method, comparisons among the individual components and their combinations were made simultaneously in order to minimize this source of variation.

Slight modifications in this test employed for specific insect species are as noted below.

. Two-spotted spider mite.In tests on two-spotted mites, the mites were confined to the upper surfacesof potted bean plants by a tanglefoot ring. The bean plants were placed in the glass tower and the mites directdusted. Mortality readings were taken in'24'hours.

Only adult mites were used in determining mortality counts.

Patented July as, 1960 3 Table 1 /NC 0 0 13. H

Oarhnmate Phosphate Rate Mortal! Dust Dust (Lbs./ Test Method Test Subieot (Percent R (Jone. Name Conc A.)

(Pcr- (Percent) cent) Pheny1. 0. 5 29. 2 Dust Tower.-. Two-Spotted Spider Mite.-. 1 Malathlon. 0.25 28. 7 fln fln 68 D0-.--.. 0.5 ...do...... 0.25 26.7 -.-,d n rln 98 This table illustrates the unexpected effectiveness of insecticidal compositions of this invention against such insects as the two-spotted spider mite.

This application is a division of copending application Serial No. 496,596, filed March 24, 1955, now abandoned, which is a continnation-in-part of Serial No. 427,374, filed May 3, 1954, now abandoned.

We claim:

1. Synergistic insecticidal compositions comprising 0, O-dimethyl S-(1,Z-dicarbethoxyethyl)dithiophosphate and phenyl carbamate, wherein said components are present in the ratio of about two parts of said carbamate per part of said dithiophosphate.

2. The method of killing insects which comprises applying to the insects and their habitat a synergistic insecticidal composition comprising 0,0-dimcthyl S-(1,2- dicarbethoxyethyl) dithiophosphate and phenyl carbamate,

wherein said components are present in the ratio of about two parts of said carbamate per part, of said dithiophosphate. a

Frear: Chem. of the Pesticides, 3rd ed., January 1955, pp. 73-91. 

2. THE METHOD OF KILLING INSECTS WHICH COMPRISES APPLYING THE INSECTS AND THEIR HABITAT A SYNERGISTIC INSECTICIDAL COMPOSITION COMPRISING O,O-DIMETHYL S-(1,2DICARBETHOXYETHYL) DITHIOPHOSPHATE AND PHENYL CARBAMATE, WHEREIN SAID COMPONENTS ARE PRESENT IN THE RATIO OF ABOUT TWO PARTS OF SAID CARBAMATE PER PART OF SAID DITHIOPHOSPHATE. 